Kyle Donald Howard, of 1310 Bayview Drive in Clearwater, died at Northside Hospital at 4:45 p.m.

According to the Pinellas County Sheriff's Office, Howard was taken to the hospital after he was found unconscious around 3:30 p.m. by another inmate who tried to wake him for dinner.

When medical staff responded, they determined Howard was not breathing and began CPR, the Sheriff's Office said. An autopsy performed Tuesday morning did not determine a cause of death. Toxicology and other tests are pending.

An investigation is ongoing, but foul play is not suspected, the Sheriff's Office said.

"There were no obvious signs of injury or physical harm," said Sheriff's Office spokeswoman Marianne Pasha.

Howard was booked into the Pinellas County Jail around 2:45 a.m. Saturday after he was arrested on probation violation charges related to his convictions in 2009 of driving under the influence and driving while his license was suspended or revoked.

He was placed in the jail's medical facility because of possible substance abuse issues, the Sheriff's Office said. Pasha declined to elaborate, citing privacy concerns, but Howard was recently arrested — on July 8 — on a charge of possession of crack cocaine.

According to detectives, Howard had said he was not feeling well and went to rest on his bunk Monday. He was later found unconscious by another inmate who tried to wake him for dinner.

Court records show Howard has been arrested several times over the past five years, mostly for misdemeanors and traffic violations. He was convicted of disorderly conduct in 2008.